Since circulating Prdx1 is closely related to chronic metabolism diseases (i.e., arteriosclerosis, diabetes, etc.)and inflammation, we hypothesized that increased circulating Prdx1 might be a biomarker of obesity, insulin resistance and NAFLD and therefore played an important role in the clinical response after LSG. The gene discussed is PRDX1; the disease is obesity due to melanocortin 4 receptor deficiency.